The metathesis of olefins consists of the exchange of groups adjacent to the double bond; between two olefin molecules, it gives the possibility of producing compounds which are difficult to synthesize by known methods. Metathesis is carried out utilizing heterogeneous or homogeneous catalysts, the catalytic systems generally employed being based upon the transition metals, W, Mo or Re. The reaction can be written diagrammatically as follows: ##STR1## R.sup.1 to R.sup.4 designate carbon chains or groups, some of which can be the same and which can carry functions, such as for example carboxyls, hydroxyls, amines, nitriles, silyls, halogens, ethers or others.
It is known that tungsten-based and rhenium-based catalyst systems can be utilized for the metathesis of functionalized olefins. The tungsten catalyst system that is known consists of WCl.sub.6 activated by a stoichiometric quantity of a tetraalkyltin reagent at 110.degree. C. (J. C. Mol J. Molec. Catal. 15 (1982) 35; J. C. Mol Chem. Tech. 13 (1983) 250; R. H. A. Bosma, G. C. N. Van den Aardweg and J. C. Mol J. Organometal. Chem. 255 (1983) 159). Variations are known such as the catalyst system consisting of WOCl.sub.4 activated by Ti(.eta..sup.5 --C.sub.5 H.sub.5).sub.2 (CH.sub.3).sub.2 (J. Tsuji and S. Hashiguchi Tet. Lett. 21 (1980) 2955), WCl.sub.6 activated with BEt.sub.3 (R. Nakamura, S. Fukuhara, S. Matsumoto and K. Komatsu Chem. Lett. (1976) 253; R. Nakamura, S. Matsumoto and E. Echigoya Chem. Lett. (1976) 1019), Mo(OEt).sub.2 Cl.sub.3 activated by BEt.sub.3 (Nakamura) and WCl.sub.6 activated by Al.sub.2 Me.sub.3 Cl.sub.3 (Nakamura).
A second catalyst system is a heterogeneous catalyst prepared by depositing Re.sub.2 O.sub.7 on silica or alumina and activating it with tetraalkyltin reagents (see articles by Mol above). It is active at room temperature.
Despite the previous studies, industrial applications of the metathesis of olefins still suffer from certain deficiencies and require improvements. In particular, the reaction is generally too slow. The invention described herein is, therefore, directed to a process for the metathesis of functionalized olefins utilizing an improved catalyst system which results in an increased rate of metathesis.